Preface to Second Edition
In an attempt to make the book more accessible the first two chapters of the first edition have been greatly expanded and split into four chapters. The first chapter covers the origin of noise research in the study of electric circuits by people like Walter Schottky, John Johnson, and Harry Nyquist. This provides a good physical example of the concept of power spectral density. Two easily constructable circuits for generating analog white noise are presented. One uses the thermal Johnson noise from a resistor. The other uses the shot noise produced by the flow of current through the reverse biased emitter-base junction of an NPN transistor.
The second chapter on digital generation of white noise is largely the same as in the first edition. The third chapter on the mathematics of noise expands somewhat on the material from the first edition by trying to motivate the use of the power spectral density function to describe random signals. This material in this chapter is not needed for the rest of the book.
The chapter on analog pink noise has been expanded to make the origin of the filter functions hopefully more clear. Several circuits that can be used to create pink noise filters are discussed and design procedures are given. These circuits are new in this edition and should hopefully make the book more useful to people who just want to generate pink noise and are not that interested in the theory.
There is much original content in this book that has not been published anywhere else as far as we know. Some of it will probably only be useful to those with a strong mathematical background. The material can be used as the starting point for further research. Engineers, physicists and mathematicians might all find interesting new research topics in this book. To help in this regard, the reading list at the end of the book has been greatly expanded.
Stefan Hollos and Richard Hollos Exstrom Laboratories LLC Longmont, Colorado April 2, 2023